When I first started taking pics, I used a clear storage tub (as a lightbox) as it filtered out the light glare, but of late, I've stopped using it altogether and have found that my pics have actually improved (probably attributed to a better understanding of camera settings).

I haven't seen any need to get a proper light box/tent thus far, but seeing as I've bought pretty much every other camera accessory already, it may be time to buy one and experiment with it.